Process for continuous hot phosgenation of amines

Abstract

This invention relates to a process for the production of organic isocyanates by the continous hot phosgenation of amines, whereby the solids are retained in the reactor by an appropriate separator and the isocyanate formed during the reaction is constantly removed from the reactor. Preferably the amount of solids of the suspension in the reactor is set so that the amount of the isocyanate taken off per unit of time reaches a maximum.

What is claimed as new and desired to be secured by Letters Patent of the United States is: 
     
       1. A process for producing organic isocyanates in high yields and of high purity by a continuous hot phosgenation reaction comprising continuously feeding into a reactor phosgene and a solvent containing either (i) an amine hydrochloride or (ii) a carbamoyl chloride-hydrochloride mixture while continuously removing, from said reactor, solvent containing the organic isocyanate thereby produced, wherein the total quantity of solids consisting of either (i) or (ii) are essentially retained in the reactor by a separator. 
     
     
       2. The process according to claim 1, wherein said carbamoyl chloride-hydrochloride mixute is produced by saturating a primary aliphatic diamine having 5-12 carbon atoms with carbon dioxide. 
     
     
       3. The process of claim 2, wherein said primary aliphatic diamine is 1,5-diamino-2-methylpentane. 
     
     
       4. The process acdording to claim 1 wherein said separator is a filter. 
     
     
       5. The process according to claim 1 wherein the solids are maintained at a constant concentration by varying the amount of (a) phosgene and (b) either amine hydrochloride or carbamoyl chloride - hydrochloride mixture added to or (c) isocyanate removed from the reactor. 
     
     
       6. The process according to claim 5 wherein said solids are maintained at a concentration range from about 3% to about 30%. 
     
     
       7. The process according to claim 6 wherein said solids are maintained at a concentration range from about 10% to about 20%. 
     
     
       8. The process according to claim 1 wherein said hot phosgenation reaction is conducted at a temperature of about 80° C. to about 200° C. 
     
     
       9. The process according to claim 1 wherein said hot phosgenation reaction is conducted at a temperature of about 80° C. to about 200° C. 
     
     
       10. The process according to claim 1 wherein said amine hydrochloride is a hydrochloride of a primary aliphatic diamine having 5-12-carbon atoms. 
     
     
       11. The process according to claim 1 wherein primary aliphatic diamines with 5-12-carbon atoms are phosgenated. 
     
     
       12. The process according to claim 1 wherein said amine hydrochloride is in admixture with carbamoyl chloride in a suitable solvent.